Many electronic devices represented by computers or the like are formed by a plurality of interconnect substrates. For example, to mount semiconductor devices such as a large scale integration (LSI) onto a motherboard and the like, these semiconductor devices are generally mounted onto, in advance, a package interconnect substrate that functions as a dedicated interconnect substrate. As high-frequency semiconductor devices have been developed recently, it has been found in some cases that electromagnetic noise generated from a high-frequency circuit electromagnetically interferes with other electronic circuits inside the electronic device, and thus obstructs operations of the electronic device.
On the other hand, an electromagnetic band gap (EBG), which is one type of meta-material, has been under development in recent years. The EBG takes a structure in which dielectrics, metals or the like are periodically disposed two-dimensionally or three-dimensionally, and form a band gap for suppressing the propagation of electromagnetic waves having a specific frequency band in the interior or on the planar surface of the structure.
For example, Patent Document 1 discloses a technique for suppressing the generation of interference between connectors of a motherboard by providing an EBG pattern in the interior of the motherboard including a multilayer interconnect structure.
Patent Document 2 discloses a technique for providing an EBG structure in a region located below a semiconductor device in an interposer.